1. Field of the Invention
The present invention relates to a head slider usually employed in a recording disk drive such as a magnetic disk drive.
2. Description of the Prior Art
A magnetic disk drive such as a hard disk drive (HDD) often employs a flying head slider. The flying head slider is adapted to fly above the surface of a magnetic disk by receiving air stream generated along the surface of the rotating magnetic disk. A transducer element embedded in the flying head slider achieves read/write operations without contacting the surface of the magnetic disk.
If a larger impact is applied to the HDD during read/write operations of the transducer element, the flying head slider collides against the magnetic disk. Even when the flying head slider is seated on the surface of the stationary magnetic disk, a larger impact applied to the HDD causes the flying head slider to bound on the surface of the magnetic disk. In any of these cases, the surface of the magnetic disk may be scratched or damaged by collision of the flying head slider.
Recently, many portable electronic devices, such as notebook-type personal computers and personal digital assistants have emerged. When recording disk drives are assembled in such portable electronic devices, a higher shock resistance is required as compared with general desktop-type or stationary electronic devices. It is preferable to avoid the surface of a recording disk from suffering from a scratch or damage even when a user drops the electronic device.
It is accordingly an object of the present invention to provide a head slider capable of contributing to improvement in shock resistance of a recording disk drive.
According to the present invention, there is provided a head slider for recording disk, comprising a chamfered vertex defined at a corner of a polygonal bottom surface surrounded by a contour separated from a contour of an air bearing surface.
In general, keen vertices are shaped at corners of the polygonal bottom surface of the head slider. It is observed that the keen vertex makes a scratch or damage on the surface of the recording disk when colliding against the surface of the recording disk. The chamfer serves to round the keen vertex, so that a scratch or damage can be restrained on the surface of the recording disk even when the head slider collides against the surface of the recording disk.
The bottom surface may comprise at least a rail swelling from a level surface of the bottom surface. In this case, a keen vertex is made at a corner of the polygonal level surface. The chamfer serves to round the keen vertex at the level surface, so that a scratch or damage can be restrained on the surface of the recording disk even when the head slider collides against the surface of the recording disk.
The chamfered vertex may be formed on a column standing on the level surface at the corner. Since the column defines a longer edge, it is possible to largely chamfer a vertex along the longer edge. The keen vertex may be largely rounded. Accordingly, a scratch or damage can reliably be restrained on the surface of the recording disk even when the head slider collides against the surface of the recording disk.
The column preferably includes a tip end aligned with the top surface of the rail. If the height of the column is aligned with the top surface of the rail in this manner, the column can normally be formed without introducing any additional process. The column can be formed at the same time in the process of forming the rail, for example.
The rail may define an air bearing surface connected to a top surface of the rail through a step formed at least at a downstream end. When air stream flows along the top surface of the rail and the step to the air bearing surface, a larger positive pressure or lift can be generated at the air bearing surface so as to keep the head slider above the surface of the recording disk.
In this case, the rail preferably comprises a front rail extending in a lateral direction of the slider near an upstream end of the slider, and a pair of rear rails spaced apart in the lateral direction near a downstream end of the slider for defining a passage of air stream therebetween. When air stream flows into a space behind the front rail in this head slider, a negative pressure can be generated between the bottom surface and the surface of the recording disk. The generated negative pressure is balanced with the positive pressure or lift at the air bearing surface so as to regulate the flying height of the head slider above the surface of the recording disk. Moreover, a pair of the rear rails serve to stabilize the behavior of the head slider in the lateral direction.
The head slider of the aforementioned type may comprise the column integrated with the front rail at its opposite ends in the lateral direction of the slider. In addition, the column may be integrated with the rear rail at one of opposite ends in the lateral direction of the slider. Such integration serves to reinforce the rigidity of the column. Moreover, if the tip end of the column is aligned with the top surfaces of the front and rear rails, the column can normally be formed without introducing any additional process. At the same time, the chamfer made on the column is prevented from affecting on the flying height of the head slider above the surface of the recording disk.
A magnetic head slider, as an example of the aforementioned head slider, can be produced by the method comprising: forming rows of transducer elements on a surface of a wafer; cutting a wafer bar out of the wafer to separate a row of transducer elements out of the rows; shaping an exposed section of the wafer bar into a bottom of a head slider for each of the transducers; and lapping the bottom of the head slider which has been cut off from the wafer bar. When the lapping process is applied to the individual head slider after separation, the keen vertices at corners of the polygonal bottom surface can reliably be chamfered.
The bottom is preferably urged against an abrasive layer spread over an elastic surface in lapping the bottom. When the bottom of the individual head slider is rubbed on the abrasive layer, the abrasive layer is deformed due to the elasticity of the elastic surface so as to contact with the periphery of the bottom of the individual head slider. The elastic deformation of the abrasive layer serves to reliably chamfer the vertices of the polygonal bottom. It is confirmed that this lapping process surely achieves the chamfer at corners of the level surface even when the rail swells on the level surface.